A 15-year-old girl had a picture involuntarily taken up her skirt while she was passed out, an investigation has found.

In April 2019, the Voyeurism (Offences) Act made ‘upskirting’ – the photography up someone’s skirt without permission – a sexual offence.

The first figures showing the impact of the act has now been obtained by Press Association and shows that almost one victim a day has contacted police in England and Wales since its introduction.

Hertfordshire Constabulary said one upskirting incident since April involved a 15-year-old boy taking an image of a 15-year-old girl while she was either drunk or asleep.

Police said the suspect then threatened to circulate the photos on social media.

The crime was confirmed, but the victim was either declined or unable to support further investigation.

Another Hertfordshire incident involved a 50-year-old woman who allegedly had a picture taken up her skirt as she was shopping for clothes in Oxfam.

The offender then ran from the store after the victim asked: “did you just try to take a picture of me up my skirt?”

Police were unable to identify the suspect.

These were the only two upskirting incidents reported in Hertfordshire between April and October 2019.

Data obtained under Freedom of Information laws from 35 police forces also found there had been 153 incidents across England and Wales reported to them in the 182 days since the law was created.

This was up from 94 incidents among 25 constabularies with available data during 2018, the year before the ban was introduced, and up from 78 reports over the two-year period from April 2015 to April 2017.

Before its introduction, campaigners complained that the lack of a specific upskirting law meant police were unsure how to deal with its allegations, and therefore many crimes went unreported.

Gina Martin led the campaign against upskirting for nearly two years after two men who took a picture up her skirt at a festival in 2017 went unpunished.

She said: "The Voyeurism Act only came into use eight months ago and the difference in charges and reporting is already up greatly.

"Among those who were charged was a convicted paedophile and a man who police subsequently found had 250,000 indecent images of children.

"Upskirting doesn't exist in a vacuum.

"Sexual assault and violence is all linked, and I'm just so happy this law is holding those who perpetrate it accountable."

Six other police forces said there was no evidence of upskirting reports in their area, and the Metropolitan Police and Bedfordshire Police refused to provide the details as per the Freedom of Information request.

The number of allegations is therefore likely to be much higher.